Microenvironment control system and method for fused deposition modeling of high-melting-point thermoplastic material

Abstract

The invention discloses a micro-environment control system and method for fused deposition modeling of a high-melting-point thermoplastic material. The high-temperature-resistant separated spray head is developed for high-melting-point thermoplastic materials, high-melting-point and high-viscosity materials, the highest heating temperature can reach 500 DEG C, the microenvironment temperature of a spray head area can be dynamically controlled according to the flow rate of thermoplastic wires, meanwhile, the heat load of mechanism movement accessories is reduced through a three-dimensional heat insulation layer, and therefore the mechanical performance is improved. And the requirements on fused deposition molding precision and performance of the thermoplastic high-melting-point PEEK can be met. And the temperature of the forming cavity is accurately controlled to be 185 + / -0.5 DEG C, and control over a wind field is increased, so that the temperature uniformity is improved, warping and deformation generated in the process that materials are converted from a semi-molten state to a solid state in the forming process are reduced, the forming precision is improved, and the printing precision and stability are ensured.

Description

Technical Field

[0001] The present application relates to the technical field of 3D printing of thermoplastic materials, and in particular to a microenvironment control system and method for fused deposition molding of high-melting-point thermoplastic materials. Background Art

[0002] Thermoplastic materials have the advantages of good adaptability to space environment, good flame retardancy, good biocompatibility, low total mass loss and condensable volatile content, good heat resistance, good wear resistance, and good mechanical properties. They meet the use requirements of the space environment and are widely used in functional components in space station cabins, environmental control and life support systems, spacecraft interior components, etc., and have great application value in the aerospace field.

[0003] There is fierce competition in domestic consumer-grade 3D printing materials, and the technical barriers for high-performance 3D printing special materials are high. Materials are often tied to production processes. Most materials are imported and are expensive, making it difficult to meet high-end manufacturing requirements. The FDM (fused deposition modeling) printer consists of a filament extrusion device and a three-dimensional motion platform. Its forming method is: by heating and melting the thermoplastic filament through the nozzle, the motor drives the extrusion nozzle to extrude according to the deposition path planned by the model file, and at the same time, the stepper motor drives the gear to squeeze the filament into the molten cavity according to the predetermined pulse. The extruded melt is bonded to the substrate, cooled and solidified, and then stacked layer by layer to form a three-dimensional product. The FDM process can realize the integrated molding of complex structures, meet personalized customization requirements, and has a short cycle and low cost.

[0004] High-performance thermoplastic materials have high melting points and high viscosity, and they have large thermal stresses during the molding process and large anisotropy at different positions. It is urgent to regulate the FDM molding process of high-melting-point thermoplastic materials to produce high-performance products. The quality and precision of fused deposition modeling parts are the key to improving fused deposition additive manufacturing technology, and the temperature control of the molding chamber of fused deposition additive manufacturing is closely related to the quality and precision of fused deposition modeling parts. Summary of the invention

[0005] The present application provides a microenvironment control system and method for the molten deposition molding of high-melting-point thermoplastic materials, with the aim of realizing FDM molding of high-melting-point thermoplastic materials in the aerospace field, meeting the molding accuracy and density requirements of the parts, and providing a technical basis for the high-value-added application of high-performance interior parts and functional parts in subsequent space station cabins, with good economic and social benefits.

[0006] In a first aspect, a microenvironment control system for melt deposition molding of high-melting-point thermoplastic materials is provided, comprising a molding chamber, a molding platform, a molding device, and a wind field auxiliary control module, wherein the molding platform and the molding device are accommodated in the molding chamber;

[0007] The molding equipment includes a motor, a heating module, a condensation module, and a printing nozzle; the printing nozzle is used to extrude the filament; the motor is used to control the flow rate of the printing nozzle, and cooperate with the movement speed of the 3D printing device to achieve continuous and controllable melt deposition molding of high-melting-point thermoplastic filaments; the heating module is used to be turned on when the flow rate of the filament is lower than a first preset flow rate to improve the fluidity of the molten filament; the condensation module is used to be turned on when the flow rate of the filament is higher than a second preset flow rate to reduce overlap defects caused by excessive flow rate of the filament;

[0008] The molding platform includes a substrate and a heating plate; the heating plate is used to heat the substrate;

[0009] The wind field auxiliary control module is accommodated in the molding chamber and is used for blowing gas in the molding chamber; the heating plate and the wind field auxiliary control module are coordinated and controlled to adjust the temperature around the molding platform to a preset molding temperature.

[0010] In combination with the first aspect, in certain implementations of the first aspect, the print head includes pre-oxidized wire reinforced SiO2 aerogel, polyimide thermal insulation pad, and 3M tape to form a three-dimensional thermal insulation layer; the pre-oxidized wire reinforced SiO2 aerogel is wrapped around the periphery of the wire flow channel, the polyimide thermal insulation pad is wrapped around the periphery of the pre-oxidized wire reinforced SiO2 aerogel, and the 3M tape forms a multi-layer winding package to cover the periphery of the polyimide thermal insulation pad.

[0011] In combination with the first aspect, in some implementations of the first aspect, the control principle of the heating plate is PID control, the input of the PID control is the control deviation signal e(t), e(t)=r(t)-y(t), r(t) is the set value of the controlled variable, and y(t) is the measured value of the controlled variable; the output of the PID control is a linear combination u(t) of the proportion, integration, and differentiation of the control deviation signal e(t),

[0012]

[0013] In the formula, K p is the proportionality coefficient; T i is the time integration constant; T D is the differential integral constant.

[0014] In combination with the first aspect, in some implementations of the first aspect, the proportionality coefficient K p The determination method includes at least one of the following:

[0015] Under pure proportional action, the proportional coefficient Kp is gradually reduced until periodic oscillation begins to occur. When periodic oscillation occurs, the proportional coefficient Kp is gradually reduced. p Gradually increase until the system is sufficiently stable;

[0016] Increasing the differential integral constant T under pure proportional actionD Stop the oscillation, and then adjust the proportional coefficient K p Gradually reduce the value to produce oscillation and increase the differential integral constant T D , so that the oscillation stops again, repeat the operation until the differential integral constant T is increased D , but it cannot stop the oscillation. At this time, the proportional coefficient K p Increase the setting until the vibration stops.

[0017] In combination with the first aspect, in some implementations of the first aspect, the differential integral constant T D Methods for determining include:

[0018] Increasing the differential integral constant T under pure proportional action D Stop the oscillation, and then adjust the proportional coefficient K p Gradually reduce the value to produce oscillation and increase the differential integral constant T D , so that the oscillation stops again, repeat the operation until the differential integral constant T is increased D , but it cannot stop the oscillation, find the differential integral constant T D The best value of .

[0019] In combination with the first aspect, in some implementations of the first aspect, the time integral constant T i The determination method includes at least one of the following:

[0020] The time integration constant T i Gradually shorten it until oscillation occurs, then extend the integration time until the oscillation stops;

[0021] The time integration constant T i Adjustment and differential integration constant T D For the same data, if oscillation occurs again, increase the time integral constant T i until the oscillation stops.

[0022] In conjunction with the first aspect, in some implementations of the first aspect, the PID control parameter satisfies at least one of the following:

[0023] Proportional control coefficient K P : 55-65%;

[0024] Integration time T I : 8-10min;

[0025] Derivative time T D : 1.5-2.5min;

[0026] In combination with the first aspect, in certain implementations of the first aspect, the applicable material of the system is any one of the following: PEEK, PEAK, PA10, PA12, PA12T.

[0027] In a second aspect, a method for a microenvironment control system for melt deposition molding of high melting point thermoplastic materials as described in any one of the implementations of the first aspect is provided, comprising:

[0028] Setting the wire flow rate and the heating temperature of the heating plate so that the substrate of the molding platform reaches a preset temperature;

[0029] During the printing process, the temperature of the printing process is controlled by the cooperation of the heating plate and the wind field auxiliary control module. The control method of the heating plate is PID control.

[0030] Using the extrusion command, the thermoplastic filament is extruded from the nozzle; the flow rate of the nozzle is controlled by the speed of the driving motor, and the movement speed of the 3D printing device is coordinated to achieve continuous and controllable melt deposition molding of high-melting-point thermoplastic filaments; the 3D printing nozzle controls the fluidity of the molten filament through the heating module and the cooling module to reduce the overlap defects caused by the excessive flow rate of the filament;

[0031] After printing is completed, keep warm for 1-1.5 hours, and take out the sample after cooling to room temperature.

[0032] In combination with the second aspect, in some implementations of the second aspect, the control method of the heating plate is PID control, the input of the PID control is the control deviation signal e(t), e(t)=r(t)-y(t), r(t) is the set value of the controlled variable, and y(t) is the measured value of the controlled variable; the output of the PID control is a linear combination u(t) of the proportion, integration, and differentiation of the control deviation signal e(t),

[0033]

[0034] In the formula, K p is the proportionality coefficient; T i is the time integration constant; T D is the differential-integral constant;

[0035] Proportional coefficient K p The determination method includes at least one of the following:

[0036] Under pure proportional action, the proportional coefficient Kp is gradually reduced until periodic oscillation begins to occur. When periodic oscillation occurs, the proportional coefficient Kp is gradually reduced. p Gradually increase until the system is sufficiently stable;

[0037] Increasing the differential integral constant T under pure proportional action D Stop the oscillation, and then adjust the proportional coefficient K p Gradually reduce the value to produce oscillation and increase the differential integral constant T D , so that the oscillation stops again, repeat the operation until the differential integral constant T is increasedD , but it cannot stop the oscillation. At this time, the proportional coefficient K p Turn it up until the oscillation stops;

[0038] Differential constant T D Methods for determining include:

[0039] Increasing the differential integral constant T under pure proportional action D Stop the oscillation, and then adjust the proportional coefficient K p Gradually reduce the value to produce oscillation and increase the differential integral constant T D , so that the oscillation stops again, repeat the operation until the differential integral constant T is increased D , but it cannot stop the oscillation, find the differential integral constant T D The best value of

[0040] Time integration constant T i The determination method includes at least one of the following:

[0041] The time integration constant T i Gradually shorten it until oscillation occurs, then extend the integration time until the oscillation stops;

[0042] The time integration constant T i Adjustment and differential integration constant T D For the same data, if oscillation occurs again, increase the time integral constant T i until the oscillation stops.

[0043] Compared with the prior art, the solution provided by this application includes at least the following beneficial technical effects:

[0044] (1) The nozzle can be separated and the control is intelligent. When FDM molding high-melting-point thermoplastic materials, the heating or condensation module can be started in real time according to the viscosity and state of the wire, and the microenvironment at the nozzle can be controlled, thereby improving and optimizing the melting and overlapping effects of the wire. The heat source can heat up or stop instantly, which is highly efficient and energy-saving.

[0045] (2) The print head area uses a thermal insulation material that is soft and easy to wrap. The inner layer is temperature controlled by a heating and condensation module. The pre-oxidized silk reinforced SiO2 aerogel effectively insulates. The polyimide thermal insulation pad maintains rigidity and local insulation. 3M tape forms a multi-layer wrapping cover. The three-dimensional thermal insulation layer can not only efficiently utilize space heating energy to meet the needs of material molten deposition molding, but also reduce waste heat radiation and reduce the thermal load of the mechanism's moving accessories.

[0046] (3) Precise regulation of the molding chamber to control the overall molding effect. At present, traditional FDM molding generally does not have the function of auxiliary wind field control in the molding chamber. It is suitable for low melting point and low viscosity material systems such as PLA, but not for high melting point thermoplastic polymer materials. When high melting point thermoplastic materials are FDM molded, the thermal stress is large. In order to reduce the influence of thermal stress during molding, it is necessary to perform auxiliary wind field control on the molding chamber. According to the glass transition temperature Tg and melting temperature Tm of the high melting point thermoplastic material, the insulation area is set to Tg+35℃<T<2 / 3Tm, which minimizes warping and deformation and achieves the best match between molding accuracy and performance.

[0047] (4) Customized high-efficiency integral molding. This type of thermoplastic material has a high melting point and glass transition temperature. The extrusion rate is controlled within the range of 55-75 mm / s. The diameter of the filament bundle under the extruder head is controlled within 0.85±0.05 mm to achieve continuous, uniform and stable material transfer, output and sintering molding, realize high-density high-temperature nylon additive manufacturing molding, and reduce defects such as pores and looseness.

[0048] (5) Traditional temperature control uses the thermocouple wire to generate a changing current as a control signal in the case of temperature changes. The use of PID control technology can reduce the risk of the operator making real-time adjustments to the temperature control according to the actual situation of manual temperature control during the test, and better solve the problem of inertial temperature error. The heating plate uses incremental PID control to control the temperature. The incremental algorithm does not need to be accumulated. The calculation accuracy problem caused by the calculation error has little effect on the calculation of the control quantity. The impact of false operation is small. If necessary, the output can be limited or prohibited through logical judgment, which will not affect the operation of the system. Therefore, high-precision control of the substrate and ambient temperature can be achieved, and near-zero warping of the sample in the FDM additive manufacturing process can be achieved.

[0049] (6) It is suitable for FDM molding of multiple series of high-melting-point thermoplastic materials and has high promotion value. Highly efficient, highly reliable and autonomously controllable FDM molding can realize rapid molding and on-demand manufacturing of high-melting-point thermoplastic materials in a wide temperature range, and has great promotion value and application prospects. FDM molding of high-melting-point thermoplastic materials in the aerospace field can meet the molding accuracy and density requirements of the parts, provide a technical basis for the high-value-added application of high-performance interior parts and functional parts in the subsequent space station cabin, and has good economic and social benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 Schematic diagram of the system for microenvironment control for melt deposition molding of high-melting-point thermoplastic materials.

[0051] Figure 2 It is a schematic diagram of the three-dimensional thermal insulation layer of the printing nozzle 4.

[0052] Figure 3 This is the schematic diagram of the PID control system. DETAILED DESCRIPTION

[0053] The present application is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0054] Figure 1 The present invention provides a micro-environment control system for high melting point thermoplastic material melt deposition molding. The system comprises a molding chamber, a molding platform, a molding device and a wind field auxiliary control module 8. The molding platform and the molding device are accommodated in the molding chamber.

[0055] The molding device includes a motor 1, a heating module 2, a condensation module 3, and a print head 4. The print head 4 is used to extrude a filament 5. The motor 1 is used to control the flow rate of the print head 4, and cooperate with the movement speed of the 3D printing device to achieve continuous and controllable melt deposition molding of high-melting-point thermoplastic filaments. The heating module 2 is used to turn on when the flow rate of the filament is lower than the first preset flow rate (the first preset flow rate is, for example, 105 mm / mim) to improve the fluidity of the molten filament. The condensation module 3 is used to turn on when the flow rate of the filament is higher than the second preset flow rate (the second preset flow rate is, for example, 105 mm / mim) to reduce the overlap defects caused by the excessive flow rate of the filament.

[0056] The molding platform includes a substrate 6 and a heating plate 7. The heating plate 7 is used to heat the substrate 6.

[0057] The wind field auxiliary control module 8 is placed in the molding chamber and used to purge gas in the molding chamber. The heating plate 7 and the wind field auxiliary control module 8 are coordinated and controlled to adjust the temperature around the molding platform to 185±0.5℃, improve the thermal stress during FDM molding, and ensure the overall molding accuracy and high performance of the product.

[0058] The microenvironment control system for high melting point thermoplastic material melt deposition molding provided by the present invention can be used to mold high melting point (melting point above 350°C, melt viscosity above 100Pa.S) thermoplastic materials (PEEK, PEAK, high temperature resistant nylon PA10, PA12, PA12T, etc.). The greater the viscosity of the wire, the worse the melt fluidity and the more difficult the molding. In view of the high melting point and high viscosity, a microenvironment controlled high temperature resistant printing nozzle 4 made of Cu-W alloy is developed, and the heating temperature can reach up to 500°C.

[0059] In some embodiments, Figure 2As shown, the print head 4 includes a pre-oxidized wire reinforced SiO2 aerogel 41, a polyimide thermal insulation pad 42, and a 3M tape 43, forming a three-dimensional thermal insulation layer. The pre-oxidized wire reinforced SiO2 aerogel 41 is wrapped around the periphery of the wire flow channel, the polyimide thermal insulation pad 42 is wrapped around the periphery of the pre-oxidized wire reinforced SiO2 aerogel 41, and the 3M tape forms a multi-layer wrapping to cover the periphery of the polyimide thermal insulation pad 42.

[0060] The print head 4 uses a heat-insulating material that is soft and easy to wrap. On the basis of the temperature control of the wire by the heating module 2 and the condensing module 3, the pre-oxidized wire reinforced SiO2 aerogel 41 effectively insulates, the polyimide heat-insulating pad 42 maintains rigidity and local heat insulation, and the 3M tape forms a multi-layer wrapping and covering. The three-dimensional heat-insulating layer can not only efficiently utilize the space heating energy to meet the needs of material molten deposition molding, but also reduce waste heat radiation and reduce the heat load of the mechanism movement accessories.

[0061] Common FDM printers are open systems that almost ignore environmental thermal control and use the overall casing to insulate heat; the filament heating power consumption is high, and the ambient temperature deviation in the cabin is large. Implementing thermal control at the print head has obvious effects, which can save energy and reduce heat consumption, with little temperature increase and low weight.

[0062] In some embodiments, the control principle of the heating plate 7 is PID (Proportional Integral Differential) control. Figure 3 This is the principle diagram of PID control. PID control is the abbreviation of proportional, integral and differential control. The principle of PID control is to calculate the controlled quantity of the controlled object based on the deviation between the actual measured value of the controlled quantity of the system and the set value, using different combinations of the three links of the deviation: proportional, integral and differential.

[0063] The input is the control deviation signal e(t) composed of the set value r(t) and the measured value y(t) of the controlled variable:

[0064] e(t)=r(t)-y(t)

[0065] Its output is a linear combination of the proportion, integration and differentiation of the deviation signal, which is also the PID control law.

[0066]

[0067] In the formula, K p is the proportionality coefficient; T i is the time integration constant; T D is the differential integral constant.

[0068] Under pure proportional action, the proportional coefficient K pFrom a larger value, it gradually decreases until periodic oscillation begins to occur. When periodic oscillation occurs, the proportional coefficient K p Gradually widen until the system is fully stable. Then change the time integration constant T i Gradually shorten until oscillation occurs, which means that the integral time is too short and the integral time should be slightly extended until the oscillation stops. Find the starting point under pure proportional action and increase the differential integral constant T D Stop the oscillation, and then adjust the proportional coefficient K p Adjust the value in stages to produce small oscillations and increase the differential integral constant T. D , so that the oscillation stops again, repeat the operation until the differential integral constant T is increased D , but it cannot stop the oscillation, find the differential integral constant T D The optimal value of the proportionality coefficient K p Adjust it slightly larger until the oscillation stops. At this time, the time integral constant T i Adjustment and differential integration constant T D If the data is close, if oscillation occurs again, increase the time integration constant T i Until the oscillation stops. This realizes the accurate feedback of PID and achieves the purpose of accurately controlling the temperature of the molding chamber.

[0069] In some embodiments, the optimized PID control parameters suitable for high melting point thermoplastic FDM molding are:

[0070] Proportional control coefficient K P : 55-65%;

[0071] Integration time T I : 8-10min;

[0072] Derivative time T D : 1.5-2.5min.

[0073] During the printing control process, when the temperature control condition is triggered, the proportional control operates normally. When the identified temperature deviation exceeds the target temperature threshold, the proportional plus integral control is used to make the system enter a steady state. When the auxiliary function of the wind field auxiliary control module 8 is turned on, the temperature of the local area on the substrate will fluctuate and change momentarily in the initial stage. At this time, the proportional plus differential control is used to improve the dynamic characteristics of the system during the adjustment process, realize quantitative monitoring and precise control of the substrate and ambient temperature, and achieve near-zero warping of the printed sample.

[0074] The present invention also provides a method for a microenvironment control system suitable for high-melting-point thermoplastic material melt deposition molding, which includes the following contents.

[0075] Step 1: Set the wire flow rate (e.g., 105±2 mm / mim) and Figure 1 The heating temperature of the heating plate 7 is set so that the substrate of the molding platform reaches a preset temperature (for example, 185±0.5°C).

[0076] The temperature of the molding platform is controlled to improve the thermal stress during FDM molding and ensure the overall molding accuracy and high performance of the parts.

[0077] Step 2: During the printing process, the temperature of the printing process is controlled by the cooperation of the heating plate 7 and the wind field auxiliary control module 8, and the control method of the heating plate 7 is PID control.

[0078] Step 3: Use the extrusion command to extrude the thermoplastic filament from the nozzle. The flow rate of the nozzle is controlled by the speed of the drive motor, and the movement speed of the 3D printing device is matched to achieve continuous and controllable molten deposition molding of high-melting-point thermoplastic filament. Figure 1 The heating module 2 and the cooling module 3 control the fluidity of the molten wire and reduce the overlap defects caused by the excessive flow rate of the wire.

[0079] Step 4: After printing is completed, keep the sample warm for 1-1.5 hours and take it out after cooling to room temperature.

[0080] In summary, the present invention has developed a high-temperature resistant separate nozzle for high-melting-point thermoplastic materials with high melting point and high viscosity. The heating temperature can reach up to 500°C. It can dynamically control the micro-environment temperature of the nozzle area according to the flow rate of the thermoplastic filament. At the same time, the three-dimensional insulation layer is used to reduce the heat load of the mechanism movement accessories, which can meet the precision and performance requirements of thermoplastic high-melting-point PEEK molten deposition molding. And the temperature of the molding chamber is precisely controlled at 185±0.5°C, and the control of the wind field is increased to improve the temperature uniformity, reduce the warping and deformation of the material during the transformation from the semi-molten state to the solid state during the molding process, improve the molding accuracy, and ensure the accuracy and stability of printing.

[0081] Although the present invention is disclosed as above in the form of a preferred embodiment, it is not intended to limit the present invention. Any person skilled in the art may make possible changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be based on the scope defined by the claims of the present invention.

Claims

1. A microenvironment control system for high melting point thermoplastic material melt deposition molding, characterized in that: It includes a molding chamber, a molding platform, a molding device and a wind field auxiliary control module, wherein the molding platform and the molding device are accommodated in the molding chamber; The molding equipment includes a motor, a heating module, a condensation module, and a printing nozzle; the printing nozzle is used to extrude the filament; the motor is used to control the flow rate of the printing nozzle, and cooperate with the movement speed of the 3D printing device to achieve continuous and controllable melt deposition molding of high-melting-point thermoplastic filaments; the heating module is used to be turned on when the flow rate of the filament is lower than a first preset flow rate to improve the fluidity of the molten filament; the condensation module is used to be turned on when the flow rate of the filament is higher than a second preset flow rate to reduce overlap defects caused by excessive flow rate of the filament; The molding platform includes a substrate and a heating plate; the heating plate is used to heat the substrate; The wind field auxiliary control module is accommodated in the molding chamber and is used for blowing gas in the molding chamber; the heating plate and the wind field auxiliary control module are coordinated and controlled to adjust the temperature around the molding platform to a preset molding temperature.

2. The system according to claim 1, characterized in that The printing nozzle includes pre-oxidized wire reinforced SiO2 aerogel, polyimide thermal insulation pad, and 3M tape to form a three-dimensional thermal insulation layer; the pre-oxidized wire reinforced SiO2 aerogel is wrapped around the periphery of the wire flow channel, the polyimide thermal insulation pad is wrapped around the periphery of the pre-oxidized wire reinforced SiO2 aerogel, and the 3M tape forms a multi-layer winding package to cover the periphery of the polyimide thermal insulation pad.

3. The system according to claim 1, characterized in that The control principle of the heating plate is PID control. The input of PID control is the control deviation signal e(t), e(t) = r(t)-y(t), r(t) is the set value of the controlled variable, and y(t) is the measured value of the controlled variable; the output of PID control is the linear combination u(t) of the proportion, integration and differentiation of the control deviation signal e(t). In the formula, K p is the proportionality coefficient; T i is the time integration constant; T D is the differential integral constant.

4. The system according to claim 3, characterized in that Proportional coefficient K p The determination method includes at least one of the following: Under pure proportional action, the proportional coefficient Kp is gradually reduced until periodic oscillation begins to occur. When periodic oscillation occurs, the proportional coefficient Kp is gradually reduced. p Gradually increase until the system is sufficiently stable; Increasing the differential integral constant T under pure proportional action D Stop the oscillation, and then adjust the proportional coefficient K p Gradually reduce the value to produce oscillation and increase the differential integral constant T D , so that the oscillation stops again, repeat the operation until the differential integral constant T is increased D , but it cannot stop the oscillation. At this time, the proportional coefficient K p Increase the setting until the vibration stops.

5. The system according to claim 3, characterized in that Differential constant T D Methods for determining include: Increasing the differential integral constant T under pure proportional action D Stop the oscillation, and then adjust the proportional coefficient K p Gradually reduce the value to produce oscillation and increase the differential integral constant T D , so that the oscillation stops again, repeat the operation until the differential integral constant T is increased D , but it cannot stop the oscillation, find the differential integral constant T D The best value.

6. The system according to claim 3, characterized in that Time integration constant T i The determination method includes at least one of the following: The time integration constant T i Gradually shorten it until oscillation occurs, then extend the integration time until the oscillation stops; The time integration constant T i Adjustment and differential integration constant T D For the same data, if oscillation occurs again, increase the time integral constant T i until the oscillation stops.

7. The system according to any one of claims 3 to 6, characterized in that The PID control parameters satisfy at least one of the following: Proportional control coefficient K P : 55-65%; Integration time T I : 8-10min; Derivative time T D : 1.5-2.5min.

8. The system according to claim 1, characterized in that Applicable materials for the system are any of the following: PEEK, PEAK, PA10, PA12, PA12T.

9. A method for a microenvironment control system for melt deposition molding of high melting point thermoplastic materials as described in any one of 1 to 8, characterized in that: include: Setting the wire flow rate and the heating temperature of the heating plate so that the substrate of the molding platform reaches a preset temperature; During the printing process, the temperature of the printing process is controlled by the cooperation of the heating sheet and the wind field auxiliary control module; Using the extrusion command, the thermoplastic filament is extruded from the nozzle; the flow rate of the nozzle is controlled by the speed of the driving motor, and the movement speed of the 3D printing device is coordinated to achieve continuous and controllable melt deposition molding of high-melting-point thermoplastic filaments; the 3D printing nozzle controls the fluidity of the molten filament through the heating module and the cooling module to reduce the overlap defects caused by the excessive flow rate of the filament; After printing is completed, keep warm for 1-1.5 hours, and take out the sample after cooling to room temperature.

10. The method according to claim 9, characterized in that The control method of the heating plate is PID control. The input of PID control is the control deviation signal e(t), e(t)=r(t)-y(t), r(t) is the set value of the controlled variable, and y(t) is the measured value of the controlled variable; the output of PID control is the linear combination u(t) of the proportion, integration and differentiation of the control deviation signal e(t), In the formula, K p is the proportionality coefficient; T i is the time integration constant; T D is the differential-integral constant; Proportional coefficient K p The determination method includes at least one of the following: Under pure proportional action, the proportional coefficient Kp is gradually reduced until periodic oscillation begins to occur. When periodic oscillation occurs, the proportional coefficient Kp is gradually reduced. p Gradually increase until the system is sufficiently stable; Increasing the differential integral constant T under pure proportional action D Stop the oscillation, and then adjust the proportional coefficient K p Gradually reduce the value to produce oscillation and increase the differential integral constant T D , so that the oscillation stops again, repeat the operation until the differential integral constant T is increased D , but it cannot stop the oscillation. At this time, the proportional coefficient K p Turn it up until the oscillation stops; Differential constant T D Methods for determining include: Increasing the differential integral constant T under pure proportional action D Stop the oscillation, and then adjust the proportional coefficient K p Gradually reduce the value to produce oscillation and increase the differential integral constant T D , so that the oscillation stops again, repeat the operation until the differential integral constant T is increased D , but it cannot stop the oscillation, find the differential integral constant T D The best value of Time integration constant T i The determination method includes at least one of the following: The time integration constant T i Gradually shorten it until oscillation occurs, then extend the integration time until the oscillation stops; The time integration constant T i Adjustment and differential integration constant T D For the same data, if oscillation occurs again, increase the time integral constant T i until the oscillation stops.

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